drm/amdgpu: validate the flush_gpu_tlb_pasid()

commit f4db991 upstream.

Validate flush_gpu_tlb_pasid() availability before flushing tlb.

Signed-off-by: Prike Liang <Prike.Liang@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: prliangpub

drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.c

@@ -737,6 +737,10 @@ int amdgpu_gmc_flush_gpu_tlb_pasid(struct amdgpu_device *adev, uint16_t pasid,
 		return 0;
 
 	if (!adev->gmc.flush_pasid_uses_kiq || !ring->sched.ready) {
+
+		if (!adev->gmc.gmc_funcs->flush_gpu_tlb_pasid)
+			return 0;
+
 		if (adev->gmc.flush_tlb_needs_extra_type_2)
 			adev->gmc.gmc_funcs->flush_gpu_tlb_pasid(adev, pasid,
 								 2, all_hub,